1. Field of the Invention
The present invention relates to a thin film transistor, a fabrication method thereof, and an organic light emitting diode (OLED) display device having the same.
2. Description of the Related Art
Flat panel display devices, such as an organic light emitting diode (OLED) display, a liquid crystal display (LCD), and the like, use thin film transistors (TFTs) as switching elements and driving elements.
Due to the development of a technique for forming a TFT at a low temperature, TFTs are formed on a flexible substrate such as transparent plastic, glass, or the like. The use of flexible substrates allows flat panel display devices to be modified to have various shapes, extending their utilization range.
A driving TFT used in an OLED display device, which is an element applying driving power to a pixel electrode in order to make an organic emission layer of an organic light emitting element in a selected pixel emit light, includes a driving gate electrode, a driving source electrode, a driving drain electrode, an active layer, and the like. A gate electrode of the driving TFT is generally formed as a single gate, and according to circumstances, the gate electrode may be configured as a so-called dual-gate formed in the form of two divided gate electrodes.
When the driving TFT having a dual-gate structure is fabricated, a connection pattern should be formed to connect the two divided gate electrodes, and here, the formation of such a connection pattern causes a spatial loss. Thus, it is difficult to implement a high resolution pane.
Also, in the related art, in order to secure a driving margin, an undoped region in which impurities are not doped is formed, or a light doping region to which impurities of a low concentration are injected, is formed in a channel region of an active layer existing between the divided gate metals. To this end, however, an additional deposition process, an additional photo process, or the like is required to prevent doping through a doping mask in performing doping on source and drain regions of the active layer.
The above information disclosed in this Background section is only for enhancement of an understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.